The invention comprises a vertically mobile press table, guided at its ends by a guiding system, similar to that of a press carriage, supported from below onto an articulated mechanism which transmits the working force to a second table, called a counter-table, joined to the press frame and over which the articulated mechanism is supported. The system is maintained rigid by an electromagnet under the counter-table which attracts a counterweight attached to its ends, when an electric current is applied. Said counterweight passes through a slot in the middle of the counter-table and is supported by four adjustable bars at the ends of a central ball-socket of the articulated device.
Under normal working conditions, the system is rigid, but when an overload control coupled to the press, detects any anomalies, wearing or breakage of a jig, offshoots or loose pieces, overheating, defects in panel feeding etc., the electric current to the electromagnet is cut, the counterweight falls and, by means of the four adjustable bars at its ends, joined to the flanges of the central ball-socket, it drags the latter, the device folds, causing the table to fall such that the jig is removed from the reach of the press carriage, avoiding damage to the jig of the press.
Between the two tables and under the electromagnet run end stops and damper cylinders compensating the end stops, allowing return to the initial work position once the anomaly has been corrected.
Rapid precision presses are machines allowing pieces to be obtained by swiftly stamping, cutting and material deformation requiring the work to be developed by the pressure or impact of a mobile element, called the carriage, on the jig, supported by another element, called a table, which is generally part of the press frame.
For some decades these machines have been improved and perfected, especially regarding their guiding systems, lubrication and carriage traction, material feeding, tools, stamping and cutting molds and matrices which have allowed their speed and yield to be increased such that in some rapid mechanical precision presses working speeds of more than one thousand impacts per minute are obtained. The cutting and stamping tools, the molds and matrices or working jigs, have been perfected and high quality materials are produced, like special steels, ceramic materials, etc. and with great precision and complexity of shape, making them more and more valuable and given the speeds that any anomaly has to be solved, a loose screw or cutting, etc. could seriously damage them.
To prevent this damage, such as the nailing of the press, many presses are provided with overloading warnings systems and carriage movement breaking systems, but due to the speed at which the latter moves, especially in fast presses, and due to its own inertia, the carriage stops after several impacts, such that in many cases, the damage has already been produced due to the carriage reaching the stopping position.